Method and apparatus for calibrating a small cell for backhaul management

ABSTRACT

The present disclosure presents a method and an apparatus for calibrating a small cell base station for backhaul management. For example, the method may include exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied, computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and adjusting one or more backhaul parameters of the small cell based on the calibration statistics. As such, calibration of a small cell base station for backhaul management may be achieved.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present application for patent claims priority to U.S. Provisional Application No. 61/897,061, filed Oct. 29, 2013, entitled “Backhaul Estimation for Small Cells—Calibration,” U.S. Provisional Application No. 61/897,064, filed Oct. 29, 2013, entitled “Backhaul Aware Load Management for Small Cells—Passive Estimation,” U.S. Provisional Application No. 61/897,069, filed Oct. 29, 2013, entitled “Backhaul Estimation for Small Cells—Light Active Estimation,” U.S. Provisional Application No. 61/897,114, filed Oct. 29, 2013, entitled “Method and Apparatus for Backhaul Congestion Estimation Using Heavy Active Probing for Small Cells,” U.S. Provisional Application No. 61/897,098, filed Oct. 29, 2013, entitled “Apparatus and Method for Off-Loading User Equipment from a Small Cell,” U.S. Provisional Application No. 61/933,732, filed Jan. 30, 2014, entitled “Backhaul Management of a Small Cell,” all assigned to the assignee hereof and hereby expressly incorporated by reference herein.

BACKGROUND

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to backhaul estimation for small cells and the like.

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. In cellular networks, macro base stations (or macro cells or conventional base stations) provide connectivity and coverage to a large number of users over a certain geographical area. To supplement macro base stations, restricted power or restricted coverage base stations, referred to as small coverage base stations or small cell base stations or small cells, can be deployed to provide more robust wireless coverage and capacity to mobile devices. For example, small cells can be deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and/or the like.

However, the deployment of small cell base stations may also encroach on the operation of other devices that typically utilize the same space, such as Wireless Local Area Network (WLAN) devices operating in accordance with one of the IEEE 802.11x communication protocols (so-called “Wi-Fi” devices) or other wired or wireless devices sharing the same Internet connection in a user's residence or office building. The unmanaged sharing of common backhaul resources may lead to various throughput and/or data integrity problems for all devices.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects not delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

The present disclosure presents an example method and apparatus for calibrating a small cell base station for backhaul management. For example, in an aspect, the present disclosure presents an example method that may include exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied, computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and adjusting one or more backhaul parameters of the small cell base station based on the calibration statistics.

Additionally, the present disclosure presents an example apparatus for calibrating a small cell base station for backhaul management that may include means for exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied, means for computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and means for adjusting one or more backhaul parameters of the small cell based on the calibration statistics.

In a further aspect, the present disclosure presents an example computer program product for computer program product for calibrating a small cell base station for backhaul of a backhaul, comprising a computer-readable medium comprising code for exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied, computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and adjusting one or more backhaul parameters of the small cell based on the calibration statistics.

Furthermore, in an aspect, the present disclosure presents an example apparatus for calibrating a small cell base station for backhaul management that may include a backhaul monitor to exchange backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied, a statistical engine to compute calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and a parameter adjuster to adjust one or more backhaul parameters of the small cell based on the calibration statistics.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of an example of an access network in which the present aspects may be implemented;

FIG. 2 is a conceptual diagram of an example communication network environment in which the present aspects may be implemented;

FIG. 3 is a conceptual diagram of another example of a communication network environment in which the present aspects may be implemented;

FIG. 4 is a flow diagram providing an overview of various aspects of backhaul estimation as contemplated by the present disclosure;

FIG. 5 is a flow diagram of an example method of backhaul link probing that may be used to characterize the backhaul link in aspects of the present disclosure;

FIG. 6 is a signaling flow diagram of an example method of inducing a full queue condition on the backhaul link suitable for calibration in aspects of the present disclosure;

FIG. 7 is a flow diagram of aspects of a method for calibrating a small cell base station for back management calibration.

FIG. 8 is a flow diagram of an example of a method for calibrating a small cell for management of a backhaul in aspects of the present disclosure;

FIG. 9 is a block diagram of an example of a NodeB in communication with a UE in a telecommunications system in which the present aspects may be implemented; and

FIG. 10 is a block diagram of an example of a small cell apparatus, represented as a series of interrelated functional modules, according to a present aspect.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

The present disclosure presents a method and apparatus for calibrating a small cell base station for backhaul management that includes exchanging backhaul probing messages with a probing server, computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages, and adjusting one or more backhaul parameters of the small cell base station based on the calibration statistics. For example, backhaul parameters of a small cell base station may be adjusted or modified based on computed calibration statistics of a backhaul of the small cell base station.

As used herein, the term “small cell” may refer to an access point or to a corresponding coverage area of the access point, where the access point in this case has a relatively low transmit power or relatively small coverage as compared to, for example, the transmit power or coverage area of a macro network based station or macro cell. For instance, a macro cell may cover a relatively large geographic area, such as, but not limited to, several kilometers in radius. In contrast, a small cell may cover a relatively small geographic area, such as, but not limited to, a home, a building, or a floor of a building. As such, a small cell may include, but is not limited to, an apparatus such as a base station (BS), an access point, a femto node, a femtocell, a pico node, a micro node, a wireless relay station, a Node B, evolved Node B (eNB), home Node B (HNB) or home evolved Node B (HeNB). Therefore, the term “small cell,” as used herein, refers to a relatively low transmit power and/or a relatively small coverage area cell as compared to a macro cell.

FIG. 1 illustrates an example wireless communication network 100 demonstrating multiple access communications, and in which the present aspects may be implemented. The illustrated wireless communication network 100 is configured to support communication among a numbers of users. As shown, the wireless communication network 100 may be divided into one or more cells 102, such as the illustrated cells 102A-102G. Communication coverage in cells 102A-102G may be provided by one or more base stations 104, such as the illustrated base stations 104A-104G. In this way, each base station 104 may provide communication coverage to a corresponding cell 102. The base station 104 may interact with a plurality of user devices 106, such as the illustrated user devices 106A-106L.

Each user device 106 may communicate with one or more of the base stations 104 on a downlink (DL) and/or an uplink (UL). In general, a DL is a communication link from a base station to a user device, while an UL is a communication link from a user device to a base station. The base stations 104 may be interconnected by appropriate wired or wireless interfaces allowing them to communicate with each other and/or other network equipment. Accordingly, each user device 106 may also communicate with another user device 106 through one or more of the base stations 104. For example, the user device 106J may communicate with the user device 106H in the following manner: the user device 106J may communicate with the base station 104D, the base station 104D may then communicate with the base station 104B, and the base station 104B may then communicate with the user device 106H, allowing communication to be established between the user device 106J and the user device 106H.

The wireless communication network 100 may provide service over a large geographic region. For example, the cells 102A-102G may cover a few blocks within a neighborhood or several square miles in a rural environment. In some systems, each cell may be further divided into one or more sectors (not shown). In addition, the base stations 104 may provide the user devices 106 access within their respective coverage areas to other communication networks, such as the Internet or another cellular network. Each user device 106 may be a wireless communication device (e.g., a mobile phone, router, personal computer, server, etc.) used by a user to send and/or receive voice and/or data over a communications network, and may be alternatively referred to as an Access Terminal (AT), a Mobile Station (MS), a User Equipment (UE), etc. In the example shown in FIG. 1, user devices 106A, 106H, and 106J comprise routers, while the user devices 106B-106G, 1061, 106K, and 106L comprise mobile phones. Again, however, each of the user devices 106A-106L may comprise any suitable communication device.

For their wireless air interfaces, each base station 104 may operate according to one of several Radio Access Technologies (RATs) depending on the network in which it is deployed, and may be alternatively referred to as a NodeB, evolved NodeB (eNB), etc. These networks may include, for example, Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, and so on. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a RAT such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a RAT such as Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2).

In cellular networks, macro base stations (or macro cells or conventional base stations) provide connectivity and coverage to a large number of users over a certain geographical area. A macro cell network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in poor user experience. Further, macro cell capacity is upper-bounded by physical and technological factors.

Thus, as discussed above, small cell base stations may be used to provide significant capacity growth, in-building coverage, and in some cases different services than macro cells operating alone, thereby facilitating a more robust user experience.

FIG. 2 illustrates an example mixed communication network environment 200 in which small cell base stations (or small cells) are deployed in conjunction with macro cell base stations (or macro cells), and in which the present aspects may be implemented.

The small cell base stations may be connected to the Internet and/or a mobile operator's network via a digital subscriber line (DSL) router or a cable modem, for example, often utilizing the existing backhaul infrastructure provided by an Internet Service Provider (ISP) for the residential home or office building in which the small cell base station is installed.

In FIG. 2, a macro cell base station 205 may provide communication coverage to one or more user devices, for example, user equipment 220, 221, and 222, within a macro cell coverage area 230 (as discussed above in more detail with reference to FIG. 1), while small cell base stations 210 and 212 may provide their own communication coverage within respective small cell coverage areas 215 and 217, with varying degrees of overlap among the different coverage areas. It is noted that certain small cells may be restricted in some manner, such as for association and/or registration, and may therefore be referred to as Closed Subscriber Group (“CSG”) cells. In this example, at least some user devices, e.g., user equipment 222, may be capable of operating both in macro environments (e.g., macro areas) and in smaller scale network environments (e.g., residential, femto areas, pico areas, etc.) as shown.

Turning to the illustrated connections in more detail, user equipment 220 may generate and transmit a message via a wireless link to the macro cell base station 205, the message including information related to various types of communication (e.g., voice, data, multimedia services, etc.). User equipment 222 may similarly communicate with small cell base station 210 via a wireless link, and user equipment 221 may similarly communicate with small cell base station 212 via a wireless link. The macro cell base station 205 may also communicate with a corresponding wide area or external network 240 (e.g., the Internet), via a wired link or via a wireless link, while small cell base stations 210 and/or 212 may also similarly communicate with network 240, via their own wired or wireless links. For example, small cell base stations 210 and/or 212 may communicate with network 240 by way of an Internet Protocol (IP) connection, such as via a Digital Subscriber Line (DSL, e.g., including Asymmetric DSL (ADSL), High Data Rate DSL (HDSL), Very High Speed DSL (VDSL), etc.), a TV cable carrying IP traffic, a Broadband over Power Line (BPL) connection, an Optical Fiber (OF) cable, or some other link. This connection may utilize the existing backhaul infrastructure provided by, for example, an ISP for the residential home or office building in which small cells 210 and 212 are installed, and may accordingly be shared among other devices operating in the same environment, such as Wireless Local Area Network (WLAN) devices operating in accordance with one of the IEEE 802.11x communication protocols (so-called “Wi-Fi” devices) or other wired or wireless devices sharing the same Internet connection in a user's residence or office building.

The network 240 may comprise any type of electronically connected group of computers and/or devices, including, for example, the following networks: Internet, Intranet, Local Area Networks (LANs), or Wide Area Networks (WANs). In addition, the connectivity to the network may be, for example, by remote modem, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5), Fiber Distributed Datalink Interface (FDDI) Asynchronous Transfer Mode (ATM), Wireless Ethernet (IEEE 802.11), Bluetooth (IEEE 802.15.1), or some other connection. As used herein, the network 240 includes network variations such as the public Internet, a private network within the Internet, a secure network within the Internet, a private network, a public network, a value-added network, an intranet, and the like. In certain systems, the network 240 may also comprise a Virtual Private Network (VPN).

Accordingly, it will be appreciated that macro cell base station 205 and/or either or both of small cell base stations 210 and 212 may be connected to network 240 using any of a multitude of devices or methods. These connections may be referred to as the “backbone” or the “backhaul” of the network, and may in some implementations be used to manage and coordinate communications between macro cell base station 205, small cell base station 210, and/or small cell base station 212. In this way, depending on the current location of user equipment 222, for example, user equipment 222 may access the communication network 240 by macro cell base station 205 or by small cell base station 210.

FIG. 3 illustrates an example communication system 300 in which a small cell base station shares a backhaul connection with other wired and/or wireless devices, and in which the present aspects may be implemented. For example, a home router 302 is installed in a user residence 304 and provides access to the Internet 306 via an Internet service provider (ISP) 308. The home router 302 communicates (e.g., transfers user data and other signaling information) with ISP 308 via a modem 315 over a corresponding backhaul link 310. In an aspect, for example, the home router 302 may support various wired and/or wireless devices, such as a home computer 312, a wireless fidelity (Wi-Fi) enabled TV 314, etc. In an additional aspect, the home router 302 may include a wireless access point (AP), for example, a Wi-Fi access point (AP) providing connectivity to such devices. In an additional aspect, for example, the home router 302 may be integrated with a wireless access point Wi-Fi AP for providing connectivity to such devices.

In an aspect, a small cell base station (or a small cell) 320 is installed in user residence 304 and serves one or more nearby user equipments (UE) 322 as described above. The small cell base station 320 via its connection to home router 302 and shared backhaul link 310 may provide access to Internet 306 and core network 316. Since the backhaul link 310 is shared between the traffic managed by small cell 320 (e.g., native traffic) and traffic generated by other devices that home router 302 may be serving (e.g., cross traffic), there is a potential for congestion of uplink (UL) traffic, down link (DL) traffic, and/or both, with varying degrees of impact on the performance of the small cell and/or other devices sharing the backhaul link 310.

Accordingly, improved backhaul aware load management for small cell base stations operating in an increasingly crowded communication environment is needed. Thus, in an aspect, small cell base station 320 may be configured to include a backhaul-aware load management (BALM) component 324 operable to mitigate congestion on backhaul link 310. The operation of BALM component 324 may enable small cell base station 320 to determine various backhaul characteristics such as, for example, sustainable throughput, and corresponding delay and jitter variations, loss, etc., to identify backhaul congestion and/or take appropriate remedial actions. For example, in an aspect, when congestion is present, operation of BALM component 324 may enable small cell base station 320 via its radio resource management (RRM) module to offload one or more UEs 322 to a macro cell base station or otherwise reduce the coverage area of small cell base station 320 in order to reduce the number of UEs 322 being served. In an additional aspect, when congestion is present, operation of BALM component 324 may enable small cell base station 320 via its RRM module to offload one or more low throughput devices to a macro cell base station and/or reduce the coverage area of small cell base station 320 (e.g., by lowering a pilot channel signal strength) in order to reduce the number of UEs 322 being served. In an additional or optional aspect, operation of BALM component 324 may enable small cell base station 320 to limit the data rate of certain flows that are not backhaul-limited (e.g., by changing a video encoding rate). In a further additional or optional aspect, operation of BALM component 324 may enable small cell base station 320 to alert the user of one of the UEs 322 and enable the user to choose one of the above-noted actions and control the operation of the small cell. For instance, a graphical user interface (GUI) may be used to alert the user, thereby allowing the user of the UE to choose one of the above-noted actions.

FIG. 4 is a flow diagram 400 providing an overview of various BALM related procedures performed by a small cell base station via operation of BALM component 324. For example, in an aspect, a small cell base station (e.g., small cell base station 320 of FIG. 3) via operation of BALM component 324 may continually or periodically monitor throughput conditions of UEs supported (e.g., camped) by the small cell base station to determine if the throughput at the UE is sufficient or otherwise acceptable (e.g., naturally low-rate traffic, Internet peer limited, etc.). If the small cell base station via operation of BALM component 324 detects that the throughput appears to be insufficient and/or unacceptable, then the small cell base station via operation of BALM component 324 may then determine whether the underlying congestion is backhaul related, air link related, located in the UE's peer, and/or simply due to a low-rate application, and may take an appropriate action. For example, in an aspect, the determination may be based on whether the backhaul has unused capacity. If the small cell base station via operation of BALM component 324 detects that the backhaul has unused capacity, the backhaul may generally have no impact on the UE experiencing a low-throughput condition.

Referring in more detail to FIG. 4, in an aspect, for each UE (e.g., each of the UEs 322 in FIG. 3), a small cell base station (e.g., small cell base station 320 in FIG. 3) via operation of BALM component 324 may perform a light passive estimation procedure to determine if the existing throughput is sufficient for the UE (decision 402). For example, the determination may be made for both for the UL, DL, and/or both, either separately or together. If the existing throughput is sufficient (‘yes’ at decision 402), there is no congestion problem for the UE and the small cell base station continues to perform light passive estimation monitoring as appropriate, as described above.

In an aspect, active initiation/generation/induction of probing packets (when compared to passive initiation/generation/induction of probing packets) can introduce probing packets in the small cell backhaul where they would not have otherwise been introduced. Passively initiated/generated/induced packets can be introduced into the network for purposes other than calibration (e.g. to/from UEs served by small cell, for small cell configuration, etc.) but such packets may to satisfy size, destination, statistics, content conditions required for calibration needs.

In an aspect, if it is determined that the existing throughput is not sufficient (‘no’ at decision 402), the small cell base station via operation of BALM component 324 checks whether it is over-the-air (OTA) capacity that is limiting the throughput (decision 404). If it is determined that the OTA capacity is limiting the throughput (‘yes’ at decision 404), the small cell base station via operation of BALM component 324 may take remedial actions to relieve the congestion on its air link, e.g., marking the UE as a candidate for handout to, e.g., a macro cell base station (block 406). In an alternate aspect, if it is determined that it is not the OTA capacity that is limiting the throughput (‘no’ at decision 404), the small cell base station via operation of BALM component 324 may perform a per-user rate shaping procedure and determine if other UEs being served by the small cell base station are limiting backhaul throughput (decision 408). In an additional aspect, if it is determined that other UEs being served by the small cell base station are limiting the backhaul throughput (‘yes’ at decision 408), the small cell base station via operation of BALM component 324 may take remedial actions, e.g., marking the user equipment as a candidate for handout to a macro cell base station (block 406).

In an aspect, if it is determined that the other UEs being served by the small cell base station are not limiting the backhaul throughput (‘no’ at decision 408), the small cell base station via operation of BALM component 324 may perform a light active estimation procedure to determine if the Internet service provider (ISP) queue is fully utilized (decision 410). A light active estimation procedure can be performed to estimate the backhaul state of actively-induced packets. The estimation procedure can use small overhead or naturally-induced/occurring packets, which are typically used to directly measure backhaul latency and loss. These small overhead or naturally-induced/occurring packets have statistical characteristics that make them a good replacement for actively-induced packets for light active estimation.

If it is determined that the ISP queue does not appear to be full (‘no’ at decision 410), there may be no backhaul capacity problem and the small cell base station via operation of BALM component 324 may revert to performing light passive estimation monitoring as appropriate, as described above. In an alternative aspect, if it is determined that the ISP queue does appear to be full (‘yes’ at decision 410), there may be a backhaul capacity problem and the small cell base station via operation of BALM component 324 may further perform a heavy active estimation procedure to determine if the throughput is being limited by congestion at the Internet peer with which the UE is communicating, rather than by the backhaul link itself (decision 412).

Similar to the light active estimation procedure, a heavy active estimation procedure can be performed to estimate the backhaul state of actively-induced packets. However, in this procedure, instead of using small overhead or naturally-induced/occurring packets, potentially high overhead or naturally-induced/occurring packets that are typically used to directly measure throughput can be used. These potentially high overhead or naturally-induced/occurring packets have statistical characteristics that make them a good replacement for actively-induced packets for heavy active estimation.

In an aspect, if it is determined that throughput is not being limited by congestion at the Internet peer with which the UE is communicating (‘no’ at decision 412), the small cell base station via operation of BALM component 324 may determine that there is a backhaul capacity problem and may take remedial actions, e.g., marking the UE as a candidate for handout to a macro cell base station (block 406). In an alternative aspect, if it is determined that the throughput is being limited by congestion at the Internet peer with which the UE is communicating (‘no’ at decision 412), there may be no backhaul capacity problem and the small cell base station via operation of BALM component 324 may revert to performing light passive estimation monitoring as appropriate, as described above.

In an aspect, in order to optimize BALM component 324 and the different BALM related procedures in FIG. 4, the small cell base station via operation of BALM component 324 may perform various calibration procedures on a continual, periodic, and/or or an event-driven basis. For example, different backhaul networks may experience congestion differently, e.g., at least in part due to the different subscription policies and schedulers used by the different ISPs to implement their respective networks. Additionally, small cell base stations are typically blind to the particular ISP implementations and pre-configurations such that accommodating all potential variations would be exhaustive if not prohibitive. Accordingly, a small cell base station operating BALM component 324 configured to perform BALM related procedures as described above may be further configured to calibrate the procedures by determining (e.g., in an automated manner) various parameters related to the backhaul implementation (referred herein as “backhaul parameters”) in which the small cell base station is deployed.

FIG. 5 is a signaling flow diagram 500 illustrating an example method performed via operation of BALM component 324 for calibrating backhaul link probing that may be used to determine one or more backhaul parameters to characterize the backhaul link. For example, in an aspect, BALM component 324 may use a time delay estimate function to generate a plurality of sample time delay measures (e.g., round-trip time (RTT) measures, from request to reply) from which various characteristics of the backhaul link may be determined and used to calibrate different estimation and management procedures used by BALM component 324.

In an aspect, a small cell base station (e.g., small cell base station 320 of FIG. 3) via operation of BALM component 324 may generate and send a number of probe packets to a probing server or other Internet peer device (block 502), including itself, via a routing node. For example, in an aspect, the probe packets may be transmission control protocol (TCP) synchronization (SYN) messages that are used to establish a basic TCP connection between two entities. In an additional aspect, the probe packet may be a hypertext transfer protocol (HTTP) “GET” request. In the course of performing any associated processing (e.g., a TCP synchronization or HTTP GET reply) (block 504), the probing server may generate and send probe responses back to the small cell base station (block 506). For example, the probe responses may be TCP SYN reset (RST) or acknowledgement (ACK) messages, e.g., used to confirm the TCP connection establishment. In an additional aspect, another type of probe response may be an HTTP GET reply, which can be used to deliver a packet of data requested by the HTTP GET request.

In an aspect, based on respective time stamps of the request probe sending and corresponding response probe reception, the small cell base station via operation of BALM component 324 may determine a RTT sample corresponding to the time delay experienced through the backhaul link (block 508). This procedure may be repeated a number of times over a given duration (e.g., an observation window) to produce a sufficient set of RTT samples. From the RTT samples collected, the small cell base station via operation of BALM component 324 may generate a RTT statistical distribution such as a cumulative distribution function (CDF) characterizing the time delays experienced over the backhaul link during the observation window (block 510).

In an additional or optional aspect, BALM component 324 may use naturally occurring RTT measures for probing and/or calibration. For example, a TCP handshake or other RTT measures with regard to servers known to not suffer from a congested link to the ISP (e.g., geographically close content delivery network (CDN) servers) may provide reliable measure of RTT and any congestion may be attributed to the small cell base station's backhaul link with the ISP rather than other links within the network.

In an aspect, BALM component 324 may use the generated backhaul RTT statistics for a variety of calibration procedures. For example, BALM component 324 may use the generated statistics for active and passive components of the BALM related procedures in FIG. 4, for example, for setting the DL and/or UL rate supported on the backhaul, light active probing statistics (e.g., thresholds) for various observed, known, or induced link conditions (e.g., no congestion, DL congestion, UL congestion, or both UL and DL congestion, etc.), and so on. In an additional aspect, based on the generated backhaul RTT statistics, BALM component 324 may determine the appropriate probing mechanisms, e.g., the type or size of UL/DL light active probes used for light active estimation, an appropriate rate and/or time window for the light active probes (e.g., for observing stable statistics), and so on.

In an additional aspect, BALM component 324 may perform calibration across several different link conditions related to the subscriber's allocated data queue at the ISP, ranging from “empty” to “full” DL and/or UL queue conditions (e.g., identified as “empty DL/UL queue calibration,” “full DL/UL queue calibration” respectively), and in different ways, making use of both natural and/or induced testing conditions (e.g., existing traffic and/or simulated traffic conditions. For example, in an aspect, BALM component 324 may assume an empty queue condition (e.g., zero or minimal traffic) and may perform calibration at certain times of day (e.g., late-night), but these conditions/calibrations may also be verified by RTT CDF characteristics generated in accordance with FIG. 5. For example, BALM component 324 may determine that a low variance in the RTT CDF or a low RTT CDF spread (e.g., [CDF_Tail_(—)90%−CDF_Tail_(—)10%]/scaling_factor<Configured_Threshold, with the scaling factor being a median, mean, and/or some other function of the CDF tail point) indicates that the samples are clustering around a stable point likely to be the empty queue delay. Similarly, BALM component 324 may assume a full DL/UL queue condition and may perform calibration when the small cell base station and/or BALM component 324 observes that utilization of its backhaul by associated UEs in a given DL/UL direction is at a maximum observed level (e.g., since boot-up, over a sliding window of time such as a month, etc.). Further, BALM component 324 may induce calibration procedures based upon initiating substantial DL/UL communications with a designated server (e.g., upon initial installation or at configured intervals).

In an aspect, BALM component 324 may perform the calibration periodically or otherwise in a periodic or repeated manner to keep the information and settings current. For example, in aspect, BALM component 324 may perform the empty queue calibration initially at boot-up and later at other configured times, which may be periodic. The periodicity may be shortened under certain conditions, however, such as if a previous empty queue calibration was determined to be insufficiently reliable (e.g., based on a scaled variance or 10%-90% scaled slope of the RTT CDF indicating excessive jitter). Further, BALM component 324 may apply a delay to active generation of calibration packets if traffic is determined to be present (e.g., UEs communicating over the small cell base station, the last calibration of probe packets having encountered a high variance (or similar statistic) of the RTT CDF, etc.).

Similarly, BALM component 324 may perform the full DL/UL queue calibration initially at boot-up and later at other configured times, which may be periodic, for example. For an actively induced full DL/UL queue condition (e.g., simulated queue conditions), BALM component 324 may advance or delay the calibration operation to coincide with other small cell traffic, so as to minimize the induced traffic load on the network. In this way, the proportion of traffic used solely for inducing the full DL/UL queue condition as compared to real user traffic may be reduced, or eliminated. Conversely, BALM component 324 may advance or delay the calibration operation based on actively-induced packets, to avoid other small cell traffic, so as to minimize the impact of the inducement on the real user traffic itself. Further, BALM component 324 may advance or delay the calibration operation to avoid cross-traffic from other devices sharing the backhaul link (e.g., as indicated by a high variance of the RTT CDF).

In an aspect, for certain backhaul estimation procedures such as light active estimation discussed above, BALM component 324 may perform an intermediate or “partial” DL/UL queue calibration. Partial DL/UL queue calibration may be performed at different times, e.g., whenever there are UEs present, and can be assisted by additional actively-induced traffic flows from the small cell base station acting as a transmitter for UL calibration, a receiver for DL calibration, or both.

FIG. 6 is a signaling flow diagram 600 illustrating an example method of operation of BALM component 324 for actively inducing a full queue condition on the backhaul link suitable for calibration. For example, the small cell base station via operation of BALM component 324 may start multiple flows with a designated server, one at a time (in the desired UL or DL calibration direction) (block 602). The small cell base station via operation of BALM component 324 then determines the average throughput of the backhaul link (e.g., via RTT measurements as described above) (block 604) and stops adding flows when the average throughput is no longer increased significantly (e.g., above a threshold) by the addition of more flows (decision 606). In an additional aspect, BALM component 324 may set an upper limit on the number of flows permitted.

Once the backhaul link has been sufficiently loaded to induce a full queue condition, the small cell base station via operation of BALM component 324 may perform full queue calibration (block 608). This multi-flow procedure ensures that the backhaul link is sufficiently loaded to induce a full queue condition while avoiding the potential problem of flow limiting, where a single larger flow may be prevented from occupying the entire subscribed bandwidth due to (calibration) server limitation, ISP flow control policy, and/or path loss or delay characteristics.

In an aspect, in order to accurately measure the average throughput on the backhaul link, BALM component 324 may allow each flow to run for a given duration (e.g., about five seconds) before determining that flow's impact on queue loading. In some aspects, BALM component 324 may run the first flow, for example, for a longer time (e.g., about thirty seconds), to exhaust a so-called “PowerBoost” credit that may be part of the subscriber's plan. For example, PowerBoost and other similar technologies may be employed by an ISP to allow higher-than-subscribed initial throughput (e.g., on the UL, DL, or both) for a short duration (or partial function of data volume), which may temporarily skew the average throughput calculation. By exhausting PowerBoost with the first flow (or a combination of first and/or subsequent flows), BALM component 324 may bring back the average throughput calculation into accordance with the sustained subscribed data rates.

In this way, the small cell base station via operation of BALM component 324 may implement an automatic determination of the number of flows need for calibration via an iterative method which checks if the aggregate throughput is within a given percentage for two sets of flows in which one has exactly one more flow than the other. Once the number of flows has been determined, BALM component 324 may use the determined number of flows as a starting point (or operating point) for subsequent calibration attempts.

In an aspect, BALM component 324 may assume the calibration statistics determined in accordance with the procedures described herein to be valid for a configured period (e.g., one week, one month, etc.), after which it may be desirable to re-run the calibration to ensure current and up-to-date information (e.g., in case the user's subscription has changed, etc.). The configured period may vary depending on several factors. For example, in an aspect, BALM component 324 may generate a statistic quality metric to identify changes in conditions that may signal the need for recalibration, e.g., the variance of probes during empty queue estimation. For example, if empty queue RTT estimates drop from a steady value of 12 ms to a new value of 5 ms, example, e.g., BALM component 324 may determine that this indicates that the user has subscribed to a higher date from the ISP. Similarly, BALM component 324 may use the scaled slope between 10% and 90% of the RTT CDF points on a sliding window as a measure of confidence related to the accuracy of the previous calibration, with more tightly clustered samples indicating a higher level of confidence.

In an aspect, there may also be variation of the derived statistics at various times of day, e.g., between times of low use (e.g., in the middle of the night) and times of high use (e.g., in the evening), and therefore BALM component 324 may run the calibration at different times of day to ensure accuracy.

In some cases, BALM component 324 may use natural calibration conditions (e.g., calibration based on traffic conditions observed during the operation of the small cell and/or UE) to trigger early recalibration. For example, if BALM component 324 observations of peak throughput during “natural” periods fail to match average observations during actively induced calibration, then BALM component 324 may determine that recalibration is needed and therefore BALM component 324 may provide an early trigger for such recalibrations in order to reconcile the discrepancy.

In an aspect, once determined, BALM component 324 may use the various calibration statistics in a variety of ways. For example, BALM component 324 may determine the subscription rate in a given DL/UL direction based on the observed full queue loading RTT. As such, BALM component 324 may use the determined subscription rate to limit the small cell bandwidth in that direction to a percentage of that rate in order to avoid unduly impacting cross-traffic from other devices sharing the backhaul link. For example, in an aspect, the small cell base station via operation of BALM component 324 may limit its bandwidth allocation to no more than 50% of the DL bandwidth or 90% of the UL bandwidth so that there will be sufficient bandwidth for cross-traffic video streaming, video conferencing, etc.

In an aspect, the example percentages described above may be fixed or variable, such that they are activated or otherwise enforced only when congestion is observed, e.g., observed via light active probing estimation. In an additional aspect, the value of the variable percentage may also be subject to calibration. For example, BALM component 324 may determine the percentage to limit the UL by jointly running UL and DL calibrations and determining the level of UL rate limitation above which the DL experience drops below an acceptable amount (e.g., when throughput drops below 90% of the subscribed level, or video pixilation or excessive buffering begins to arise), and vice versa. This addresses the problem where UL congestion may cause uneven delay and loss of UL control (e.g., TCP ACK) messages, which, in turn, limit DL throughput (and vice versa in the opposite UL/DL direction).

In an aspect, BALM component 324 may use natural calibration opportunities instead of or as an enhancement to the statistics derived from induced calibration conditions. For example, BALM component 324 may improve light active calibration based on observed statistics during light active probing. For example, the “leftmost” (e.g. low CDF percentile) RTT CDF samples can be used to improve empty queue statistics. For example, in some designs, the “leftmost” shorter RTT CDF samples may be included only if passive estimation shows low small cell usage. In an additional example, the “rightmost” (e.g. high CSF percentile) RTT CDF samples may be used to improve full queue statistics. In an aspect, heavy active probes may also be improved based on observed statistics during normal small cell operation.

In an aspect, during natural calibration monitoring, BALM component 324 may determine peak throughput from the highest or second highest (non-zero) CDF statistical mode observed (e.g., as derived from a Fast Fourier Transform (FFT) of the CDF). The use of the second highest mode may be useful to filter out PowerBoost spikes of the type noted above, which may artificially inflate the observed throughput. In addition, DL and UL throughput will usually be different, and can be identified based on different CDF modes, with the DL mode typically appearing in a lower RTT range as compared to the UL mode. For example, if one mode appears around 20 ms whereas a second mode appears around 100 ms, the 20 ms mode will most likely correspond to the DL RTT and associated throughput while the slower 100 ms mode will most likely correspond to the UL RTT and associated throughput.

In some situations, there may not be a single set of statistics that accurately reflects an entire time period of interest (e.g., an entire day or week or month). This is because the calibrated statistics may change over time, but nevertheless may follow certain periodic patterns. For example, RTT observations taken during the middle of the night may be representative of nightly observations but different from those taken in the evening or afternoon. Similarly, RTT observations taken on weekends may be representative of week-end observations but different than those taken on weekdays. Accordingly, BALM component 324 may associate different sets of statistics with the different time periods (e.g., hourly RTTs, hourly UL peak rates, etc.) and may independently determine/employ such sets of statistics (e.g., Monday's calibration data at 1 pm may be used for next Monday's calibration at 1 pm, with other sets of statistics being used for other intervening time periods). In an additional aspect, BALM component 324 may give a higher weight, e.g., greater consideration, to more recent RTT observations.

Returning to FIG. 4, BALM component 324 may use the calibration statistics discussed above to set various parameters of the different backhaul estimation procedures described. For example, for light active estimation, BALM component 324 may use the calibration statistics to set thresholds corresponding to full and empty queue states, which may be employed in the light active estimation to determine when observed queue conditions should be considered as full or empty. They may also be used to set the sampling rate at which the light active estimation is performed, calibrated to obtain stable statistics without unduly burdening the network, and in some instances, variable based on time of day calibrations, etc. As another example, for heavy active estimation, BALM component 324 may use the calibration statistics to calibrate the early termination of a proxy flow (e.g., flow use for heavy active estimation as representative/proxy of real flow performance) as a function of a desired minimum average throughput, or by determining what the short-term average/tail throughput should be to guarantee a desired long-term average or tail throughput.

FIG. 7 is a flow diagram 700 illustrating an example method used in an aspect of the operation of BALM component 324 for calibrating a small cell base station for backhaul management.

In an aspect, at block 710, methodology 700 may include exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell. For example, in an aspect, BALM component 324 may cause backhaul probing messages to be exchanged between small cell base station 320 and a probing server. The exchanging of the probing messages is performed over backhaul 310. In an additional aspect, the exchanging of the probing message is performed after determining that a full queue condition (e.g., a potential full queue condition based on determining that there is no further increase in throughput, or a set/computed number of maximum number of induced flows has been reached) associated with backhaul 310 is satisfied. In an additional aspect, the probing packets may be initiated passively or actively.

In an aspect, at block 720, methodology 700 may include computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages. For example, in an aspect, BALM component 324 may compute calibration statistics (e.g., sustainable throughput, corresponding delay, loss and jitter variations, etc.) at small cell base station 320 based on characteristics associated with the backhaul probing messages.

In an aspect, at block 730, methodology 700 may include adjusting one or more backhaul parameters of the small cell based on the calibration statistics. For example, in an aspect, BALM component 324 may adjust backhaul parameters (e.g., thresholds corresponding to full and empty queue states) of the small cell 320 based on the computed calibration statistics. In an additional aspect, traffic rate allocation (e.g. to cellular traffic, Wi-Fi traffic) thresholds may be adjusted as a function of observed (e.g., via calibration) subscription rates. In a further additional aspect, bandwidth reservation may be performed for particular kinds of traffic (e.g. bandwidth reserved for non-small cell traffic sharing backhaul with the small cell, by rate-limiting small cell traffic). In yet another aspect, calibrated observation may inform decision about the acceptability of serving particular kinds of traffic (e.g. voice traffic may not be served on a high-latency, high-loss, or high jitter backhaul). In yet another aspect, calibrated rates may inform small cell configuration (e.g., transmit power, schedule) priorities.

FIG. 8 illustrates an aspect of the configuration of BALM component 324 in an example small cell base station 800 for backhaul aware load management calibration. In this example, the small cell base station 800 is deployed in the vicinity of one or more client devices 840, such as the UEs 322 in FIG. 3, and a router 830 providing Internet access, such as the home router 302 in FIG. 3. It should be noted that BALM component 324 may include all or some portion of the following, or may include a separate portion of some of these components that are in communication with remaining ones of these components.

In general, the small cell base station 800 and/or BALM component 324 includes various components for providing and processing services for the client devices 840. For example, the small cell base station 800 may include a transceiver 812 for wireless communication with the one or more of the clients 840 and a backhaul controller 814 for backhaul communications with other network devices, such as the router 830. These components may operate under the direction of a processor 816 in conjunction with memory 818, for example, all of which may be interconnected via a bus 820 or the like.

In addition and in accordance with the discussion above, the small cell base station 800 and/or BALM component 324 may also further include a backhaul monitor 822 for exchanging backhaul probing messages with a probing server, a statistical engine 824 for computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages (e.g., from an RTT sample database 819 stored in the memory 818), and a parameter adjuster 826 for adjusting one or more backhaul parameters of the small cell base station 800 based on the calibration statistics.

For example, in an aspect, backhaul monitor 822 may be configured to exchange backhaul probing messages with a probing server by initiating a plurality of probing messages at the small cell base station (e.g., small cell base station 320). In an additional aspect, the exchanging of the probing messages may be performed over a backhaul (e.g., backhaul 310) after determining that a full queue condition associated with the backhaul is satisfied.

For example, in an aspect, statistical engine 824 may be configured to computing calibration statistics for the backhaul (e.g., backhaul 310) based on characteristics associated with the backhaul probing messages. Additionally, for example, in an aspect, parameter adjusted 826 may be configured to adjusting one or more backhaul parameters of the small cell base station based on the calibration statistics.

In an aspect, the small cell base station 800 and/or BALM component 324 may further include an ISP queue controller 828 for determining that an ISP data queue associated with an ISP subscriber is substantially full or empty prior to performing the exchanging, and in some aspects inducing the ISP data queue to be substantially full prior to performing the exchanging by starting one or more traffic flows. In an additional aspect, the small cell base station 800 and/or BALM component 324 may further include a throughput monitor 829 for deriving an average uplink or downlink throughput of the backhaul link from a corresponding CDF distribution. It will be appreciated that in some designs one or more or all of these operations may be performed by or in conjunction with the processor 816 and memory 818.

FIG. 9 illustrates in more detail the principles of wireless communication between a wireless device 910 (e.g., small cell base station 320 of FIG. 3), including BALM component 324, and a wireless device 950 (e.g., UE 322 of FIG. 3) of a sample communication system 900 that may be adapted as described herein. In an aspect, the functionality of BALM component 324 may be in one or more modules or instructions within processor 930, or within computer readable instructions stored in memory 932 and executable by processor 930, or some combination of both.

At the device 910, traffic data for a number of data streams is provided from a data source 912 to a transmit (TX) data processor 914. Each data stream may then be transmitted over a respective transmit antenna.

The TX data processor 914 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data. The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by a processor 930. A data memory 932 may store program code, data, and other information used by the processor 930 or other components of the device 910.

The modulation symbols for all data streams are then provided to a TX MIMO processor 920, which may further process the modulation symbols (e.g., for OFDM). The TX MIMO processor 920 then provides NT modulation symbol streams to NT transceivers (XCVR) 922A through 922T. In some aspects, the TX MIMO processor 920 applies beam-forming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transceiver 922 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NT modulated signals from transceivers 922A through 922T are then transmitted from NT antennas 924A through 924T, respectively.

At the device 950, the transmitted modulated signals are received by NR antennas 952A through 952R and the received signal from each antenna 952 is provided to a respective transceiver (XCVR) 954A through 954R. Each transceiver 954 conditions (e.g., filters, amplifies, and down converts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

A receive (RX) data processor 960 then receives and processes the NR received symbol streams from NR transceivers 954 based on a particular receiver processing technique to provide NT “detected” symbol streams. The RX data processor 960 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by the RX data processor 960 is complementary to that performed by the TX MIMO processor 920 and the TX data processor 914 at the device 910.

A processor 970 periodically determines which pre-coding matrix to use (discussed below). The processor 970 formulates a reverse link message comprising a matrix index portion and a rank value portion. A data memory 972 may store program code, data, and other information used by the processor 970 or other components of the device 950.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 938, which also receives traffic data for a number of data streams from a data source 936, modulated by a modulator 980, conditioned by the transceivers 954A through 954R, and transmitted back to the device 910.

At the device 910, the modulated signals from the device 950 are received by the antennas 924, conditioned by the transceivers 922, demodulated by a demodulator (DEMOD) 940, and processed by a RX data processor 942 to extract the reverse link message transmitted by the device 950. The processor 930 then determines which pre-coding matrix to use for determining the beam-forming weights then processes the extracted message.

FIG. 9 also illustrates that the communication components may include one or more components that perform calibration for management of a backhaul link to an ISP as taught herein. For example, a communication (COMM.) component 990 may cooperate with the processor 930 and/or other components of the device 910 to perform the calibration as taught herein. Similarly, a communication control component 992 may cooperate with the processor 970 and/or other components of the device 950 to support the configuration as taught herein. It should be appreciated that for each device 910 and 950 the functionality of two or more of the described components may be provided by a single component. For example, a single processing component may provide the functionality of the communication control component 990 and the processor 930 and a single processing component may provide the functionality of the communication control component 992 and the processor 970.

FIG. 10 illustrates an example small cell apparatus 1000, including BALM component 324, represented as a series of interrelated functional modules. In an aspect, small cell apparatus 1000 and/or BALM component 324 may include a module for exchanging 1002 that may correspond at least in some aspects to, for example, a communication device (e.g., a backhaul port) as discussed herein, a module for computing 1004 that may correspond at least in some aspects to, for example, a processing system as discussed herein, and/or a module for adjusting 1006 that may correspond at least in some aspects to, for example, a processing system as discussed herein.

The functionality of the modules of FIG. 10 may be implemented in various ways consistent with the teachings herein. In some aspects, the functionality of these modules may be implemented as one or more electrical components. In some aspects, the functionality of these blocks may be implemented as a processing system including one or more processor components. In some aspects, the functionality of these modules may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Thus, the functionality of different modules may be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Also, it should be appreciated that a given subset (e.g., of an integrated circuit and/or of a set of software modules) may provide at least a portion of the functionality for more than one module.

In addition, the components and functions represented by FIG. 10 as well as other components and functions described herein, may be implemented using any suitable means. Such means also may be implemented, at least in part, using corresponding structure as taught herein. For example, the components described above in conjunction with the “module for” components of FIG. 10 also may correspond to similarly designated “means for” functionality. Thus, in some aspects one or more of such means may be implemented using one or more of processor components, integrated circuits, or other suitable structure as taught herein.

In some aspects, an apparatus or any component of an apparatus may be configured to (or operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.

Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

Accordingly, an aspect disclosed can include a computer readable media embodying a method for calibrating a small cell base station for management of a backhaul link to an ISP. Accordingly, the invention is not limited to illustrated examples and any means for performing the functionality described herein are included in aspects disclosed.

While the foregoing disclosure shows illustrative aspects disclosed, it should be noted that various changes and modifications could be made herein without departing from the scope of the invention as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects described herein need not be performed in any particular order. Furthermore, although elements disclosed may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium. The computer-readable medium may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disk (CD), digital versatile disk (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer.

The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium may be resident in the processing system, external to the processing system, or distributed across multiple entities including the processing system. The computer-readable medium may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 

What is claimed is:
 1. A method for calibrating a small cell base station for backhaul management, comprising: exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied; computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages; and adjusting one or more backhaul parameters of the small cell base station based on the calibration statistics.
 2. The method of claim 1, wherein computing the calibration statistics comprises: computing the calibration statistics based on a round-trip time (RTT) distribution or a latency distribution associated with the backhaul probing messages.
 3. The method of claim 2, wherein the RTT distribution comprises a cumulative distribution function (CDF) characterizing time delays experienced over the backhaul during an observation window.
 4. The method of claim 1, wherein computing the calibration statistics comprises: computing the calibration statistics based on throughput observations associated with the backhaul probing messages.
 5. The method of claim 4, further comprising: determining an average uplink or downlink throughput of the backhaul from the throughput observations; and wherein the calibration statistics comprise the average uplink or downlink throughput.
 6. The method of claim 1, wherein exchanging the backhaul probing messages comprises: generating the backhaul probing messages by active probing or using preexisting probing messages by natural probing.
 7. The method of claim 1, wherein the exchanging of the backhaul probing messages with the probing server includes exchanging the backhaul probing messages with a dedicated calibration server or a content delivery network (CDN) server or a server in a node, wherein the node is a small cell base station.
 8. The method of claim 7, wherein the probing packets are routed via a third party node when the server is located in a small cell base station.
 9. The method of claim 8, where the third party node is a node that establishes routable tunnels with the small cell base stations.
 10. The method of claim 1, wherein the adjusting comprises: adjusting at least one of an uplink or downlink rate supported on the backhaul, a light active probing threshold, a size of light active probes used for light active estimation, a rate for the light active probes, and a time window for the light active probes.
 11. The method of claim 1, further comprising: periodically repeating the exchanging, the computing, and the adjusting.
 12. An apparatus for calibrating a small cell base station for backhaul management, comprising: means for exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied; means for computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages; and means for adjusting one or more backhaul parameters of the small cell based on the calibration statistics.
 13. The apparatus of claim 12, wherein the means for computing calibration statistics comprises: means for computing calibration statistics based on a round-trip time (RTT) distribution or a latency distribution associated with the backhaul probing messages.
 14. The apparatus of claim 13, wherein the RTT distribution is a cumulative distribution function (CDF) characterizing time delays experienced over the backhaul during an observation window.
 15. The apparatus of claim 12, wherein the means for computing calibration statistics comprises: means for computing calibration statistics based on throughput observations associated with the backhaul probing messages.
 16. The apparatus of claim 15, further comprising: means for determining an average uplink or downlink throughput of the backhaul from the throughput observations, and wherein the calibration statistics comprise the average uplink or downlink throughput.
 17. A computer program product for calibrating a small cell base station for backhaul of a backhaul, comprising: a computer-readable medium comprising code for: exchanging backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied; computing calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages; and adjusting one or more backhaul parameters of the small cell based on the calibration statistics.
 18. The computer program product of claim 17, wherein the code for computing the calibration statistics comprises code for computing the calibration statistics based on a round-trip time (RTT) distribution or a latency distribution associated with the backhaul probing messages.
 19. The computer program product of claim 18, wherein the RTT distribution is a cumulative distribution function (CDF) characterizing time delays experienced over the backhaul during an observation window.
 20. The computer program product of claim 17, wherein the code for computing the calibration statistics comprises code for computing the calibration statistics based on throughput observations associated with the backhaul probing messages.
 21. The computer program product of claim 17, wherein the code for exchanging of backhaul probing messages comprises: code for generating the backhaul probing messages by active probing or using preexisting probing messages by natural probing.
 22. An apparatus for calibrating a small cell base station for backhaul management, comprising: a backhaul monitor to exchange backhaul probing messages with a probing server by initiating a plurality of probing packets at the small cell base station, wherein the exchanging is performed over a backhaul after determining that a full queue condition associated with the backhaul is satisfied; a statistical engine to compute calibration statistics for the backhaul based on characteristics associated with the backhaul probing messages; and a parameter adjuster to adjust one or more backhaul parameters of the small cell based on the calibration statistics.
 23. The apparatus of claim 22, wherein the statistical engine is further configured to compute calibration statistics based on a round-trip time (RTT) distribution or a latency distribution associated with the backhaul probing messages.
 24. The apparatus of claim 23, wherein the RTT distribution is a cumulative distribution function (CDF) characterizing time delays experienced over the backhaul during an observation window.
 25. The apparatus of claim 22, wherein the statistical engine is further configured to compute calibration statistics based on throughput observations associated with the backhaul probing messages.
 26. The apparatus of claim 25, further comprising: a throughput monitor configured to determine an average uplink or downlink throughput of the backhaul from the throughput observations, and wherein the calibration statistics comprise the average uplink or downlink throughput.
 27. The apparatus of claim 22, wherein the backhaul monitor is further configured to generate the probing messages by active probing or using preexisting probing messages by natural probing.
 28. The apparatus of claim 22, wherein the probing server is a dedicated calibration server or a Content Delivery Network (CDN) server.
 29. The apparatus of claim 22, wherein the parameter adjuster is further configured to adjust at least one of an uplink or downlink rate supported on the backhaul, a light active probing threshold, a size of light active probes used for light active estimation, a rate for the light active probes, and a time window for the light active probes.
 30. The apparatus of claim 22, where in the backhaul monitor, statistical engine, and the parameter adjuster are respectively further configured to periodically repeat the exchange of backhaul probing message, compute calibration statistics, and adjust one or more backhaul parameters. 